Hinged last



Patented Jan. 30, 1940 UNITED STATES PATENT oFFlcE HINGED LAST AlexanderW. McNeill, Lynn, Mass.

Application May 11, 1939, Serial No. 273,022

5 Claims.- (Cl. 12-136) This invention relates to hinged lasts andconslsts in an improved link or hinge member constructed to perform theusual functions of keeping the toe and heel parts of the last together 5and of maintaining the last in either open or closed position.

The most important object of my invention is to provide a more durableand eillcient last by employing a novel link which requires the 10minimum amount of Working space in the interior of the last parts andwhich securely holds the parts together against relative longitudinaldisplacement.

Many lasts as heretofore lconstructed have been 15 unsatisfactory fromthe standpoint of durability because the extreme pressures encounteredin the levelling, sole pressing, and cement sole attaching operationstend to break down the lasts in the areas where the parts have beenweakl ened to provide working space for the hinge members which holdsthe last parts together. Furthermore the .design of many links now inuse is such that the links elongate and the parts of the last arepermitted to separate to an ob- 35 jectionable extent under pressuresordinarily encountered in shoemaking operations.

An important advantage of my invention resides in the fact that my novellink may yield Without danger of breaking and without per- 30 marientelongation and does not permit separation of the parts of the lastexcept under extraordinary or abnormal pressures Where a slightseparation is desirable because it saves the wood and prevents breaking.l

35 To accomplish the objects and secure the advantages outlined above Iemploy a link com- Drising one or more thin dat metal stampings formedas closed bodies wherein one side member is curved more than the otherside member,

vo an internal arcuate slot separating the sides of the link anddefining their shape. The ends of the slot are engaged by the usualanchor pins passing transversely through the heel and toe parts of thelast. 'Ihe anchor pins are so located that in their normal positions aline connecting their centers falls to one side of the axis of rotationof the two parts of the last, it being understood that the parts of thelast are provided with interfltting curved surfaces to pro- 50 vide forrelative rotation of the heel and toe parts about a fixed axis. As onepart of the last is rotated about this axis the link is forced tolengthen out in toggle action as the center line of the two anchor pinspasses across the 55 axis of rotation. After the center linehas passedthe axis of rotation tension on the link is relieved, although in closedposition of the last the link is maintained under tension so that thetwo parts are held firmly in operative position. As the side of the linkwith the greater curve 5 fiexes, it is checked and guided by therelatively stiffer side with the lesser curve.

These and other features and advantages of the invention will best beunderstood and appreciatedfrom the following description of a preferredembodiment thereof, selected for purposes of illustration and shown inthe accompanying drawing, in which:

Fig. 1 is a view in side elevation of a last in closed position withportions broken away to expose the link construction,

Fig. 2 is a view in cross-section along the line 2-2 of Fig. 1,

Fig. 3 is a view in side elevation of a link constructed according to myinvention and showing in dotted lines its action under longitudinaltension,

Figs. 4 and 5 are views in cross-section through the center of a lastshowing the parts in collapsed and intermediate position respectively.

As shown in Fig. 1, the last of my invention includes a heel part I0provided with the usual comb plate I1 and a metal plate I3 secured tothe last bottom by screws I9 and bynails 23. The heel part I0 isprovided at its forward end 30 With a hinge projection II of circularcontour which extends transversely across the front of the heel part.The last alsov includes a toe part I4 provided at its rear end with atransverse concave depression into which the projection II fits closelyso that the parts I0 and I4 may be relatively rotated upon the line I2as an axis.

The heel part II is bored to receive an anchor pin I5 which is parallelto the line I2, and o the toe part u is provided with a simuar anchor 4pin I8. The pins I5 and I6 are so located that when the last iscollapsed as shown in Fig. 4 or closed as shown in Fig. 1, a lineconnecting their centers falls to one side or the other of 5 the axis ofrotation represented by the line I2.

The anchor pins I5 and I6 are connected by one or more links 20 each ofwhich is a plate or stamping of spring steel or other tough resilientmetal formed as a closed body having 60 relatively long spaced sidemembers or glands and a centrally located arcuate slot provided withenlarged ends to fit the anchor pins I5 and I6. The two side members ofthe link are approximately of the same width and merge at their endsinto the rounded ends of the body of the link. As shown in Fig. 3, thelower side member of the link 2B has a pronounced concave curve, and anupper side member which is almost straight or slightly convex. Fig. 2shows how a plurality of links 20 may be used in a last if desired. Itis desirable to use a plurality of relatively thin links rather than asingle thick link because of the convenience with which the thinnerlinks may be stamped from sheet steel, but the employment of a singlelink is within the scope of my invention.

When the last is closed as illustrated in Fig. 1 the line connecting thecenters of the anchor pins falls slightly below the axis I2 of rotationof the parts of the last. In intermediate position, as shown in Fig. 5.the center line of the anchor pins intersects the axis I2, and incollapsed position the center line is above the axis I2. The distancebetween the anchor pins I5 and I6 is the same except when they are inalignment with the axis of rotation of the last parts. However, when theaxis I2 intersects the center line of the anchor pins, the distancebetween the pins is increased, and the links 20 must elongate in orderto permit such movement of the last parts. The last is thus locked inclosed position and can only be broken when the toe portion is movingupwardly with sumcient force to elongate the link in carrying over thedead center.

It will be apparent from an inspection of Fig. 3 that the lower sidemember of the link is curved so that it can be flexed and therebylengthened, but the substantially straight upper side member acts as acheck and makes it harder to ex the link as a whole. The upper sidemember acts as a relatively stiff beam when the lower side member isstraightened in flexing and limits the ends of the link to outwardmovement as shown in dotted lines in Fig. 3. The

upper member itself may be very slightly deilected in this action. Theresilient tension thus created is such that the link 20 will snap thelast either to closed or collapsed position when the parts are onceforced past the dead center.

It is apparent from Fig. 2 that the use of links constructed accordingto my invention requires that only a narrow slot be cut into the partsof the last. Since a minimum amount of wood is removed, the last is notseriously weakened as is the case where more bulky links are used.Furthermore the slot in the heel part does not interfere with the screwsI9 used to secure the metal heel plate I3 to the last bottom, a distinctadvantage in the manufacture of lasts. As shown in Fig. 1 the butt ofthe toe part below the circle cut is perfectly solid and not interruptedto provide working space for the link 20.

The links are so dimensioned that the anchor pins I5 and I6 exertconsiderable pull tending at all times to distort the link 2l) and toforce the parts of the last together, a pull which resists the stressesordinarily encountered in shoemaking operations. If excessive andextraordinary pressure is applied, the parts will separate slightly andyield so that there is little danger of breaking the wood of the last. l

It will be understood that the degree of curvature of the sides of thelink is not critical, but that the one side must be curved more than theother so that it will flex more readily than the other if the desiredadvantages are to be secured. In links heretofore used it has beennecessary to leave clearances so'that the parts f the last could berotated, with the result that when the last was in either normalposition, the parts were loosely held together. 'I'he link of myinvention, due to its self-contained spring action, holds the parts ofthe last tightly together at all times and in all relative positions ofthe Parts of the last.

It will beunderstood that the links 20 are slightly elongated at alltimes when the last is closed so that the parts arev then held closely10 together. The links are further elongated as the parts of the lastare rotated upon each other in passing over the dead center position.

I contemplate the use of either one or a plurality of links in a last,according to the size and weight of the last. Where a single link isused it may conveniently be formed of thicker metal than would beemployed where a plurality of links are used.

The foregoing description relates to but one zo expression of the spiritof my invention and will serve as an illustration of a structure inwhich my invention can be visualized. However, my invention is limitedneither by the materials mentioned in the description nor by theconguration of the elements shown in the drawing, since there are manypossible embodiments of my invention in which the shapes and materials0f the elements and their relative locations may differ considerablyfrom those specifically disclosed above. For example, the links may beinverted and still function equally as well as in the position shown inthe drawing. The determination of the scope of my invention by means ofthe appended claims should be carried out with this paragraph in mind.

Having thus described my invention, what l' claim as new and desire tosecure by Letters Patent of the United States is:

1. An improved last comprising heel and toe 40 parts having interttingcurved surfaces shaped to permit relative rotation of the parts about axed axis, a last hinge link including a closed exible body havingcontinuous side members curved unequally and separated by a curved slot,a and a pair of anchor pins disposed transversely through the toe andheel parts respectively and passing through said closed body and solocated that in their normal position a 'line passing through theircenters falls to one side of the axis m of rotation of the parts of thelast.

2. A last hinge comprising a single piece of sheet steel provided with acentrally located longitudinally curved slot having enlarged ends, thepiece being shaped so that the slot divides its major portion into asubstantially straight side member and a ilexible curved side member.

3. An improved last comprising toe and heel parts having curvedintertting surfaces to permit relative rotation of the parts, a linkincluding a closed body having side members of unequal curvatureseparated throughout their length by a curved slot, and anchor pinsdisposed in said toe and heel parts and maintain ing said link underyielding tension, whereby Said link holds said parts firmly together.

4. An improved last comprising toe and heel parts having curvedintertting surfaces to permit relative rotation of the parts, aplurality of links each of which comprises a closed body of sheet steelhaving side members of unequal curvature separated throughout theirlength by a curved slot, and anchor pins disposed in said toe and heelparts for maintaining said links in elongated condition to create ayielding tension holding said toe and heel parts rmly tially equalwidth, one of said side members betogether. ing slightly curved and theother having a; pro- 5. A last link comprising a at sheet metal nouncedcurvature whereby the later is rendered body, resilient in character,having rounded ends substantially more exible under tension than 5 anda. curved longitudinal slot dening in the the less curved side member. 5

body of the link two side members of substan- ALEXANDER W. McNEILL.

